If you've got the right design and the right budget and you plan to keep the vehicle for a while, this would be a good option for you. Vehicle wraps can run from about $2500 and up depending on the size of the vehicle.
This may not be the right option if your going to be changing the vehicle soon. When it comes to selling your vehicle (or lease return) keep in mind the cost of removing the wrap, even if you choose to remove it your self its no easy task. Being it that we are in Vancouver its even harder to remove the wraps as its only warm for a couple of months (hot weather helps to remove vinyl).
In my opinion, most of the time Decals are the way to go. They are less costly, you can get decals starting at $120 installed. They are easy to remove if you need to change your info (like change of a website or email address). Most decals jobs will only run about $360 and gets you graphics on three sides (Back, driver side and passenger side).
In a lot of cases full wraps can be made more effective just using decals. Messages can sometimes be lost on a full wrap, even though the overall wrap might look really cool. Usually Decals are eye catching and easy to read, all you need is an eye catching design.
At the end of the day both options are great as long as they do what you want them to do (that is usually to get you more customers), it more depends on each person circumstance.